An organic electroluminescence device (also referred to as “organic EL device”) is generally composed of an anode, a cathode, and one or more organic thin film layers which comprise a light emitting layer and are sandwiched between the anode and the cathode. When a voltage is applied between the electrodes, electrons are injected from the cathode and holes are injected from the anode into a light emitting region. The injected electrons recombine with the injected holes in the light emitting region to form excited states. When the excited states return to the ground state, the energy is released as light. Therefore, it is important for increasing the efficiency of an organic EL device to develop a compound which transports electrons or holes into a light emitting zone efficiently and facilitates the recombination of electrons and holes.
The lower voltage drive of an organic EL device is effective for reducing the power consumption and also effective for improving the emission efficiency and the device lifetime. To reduce the driving voltage, a charge transporting material having a high mobility to electrons and/or holes is required, and many proposals have been made on such a charge transporting material.